Still have black screen that is registering properly. Also plugging a display into the DisplayLink hub crashed the logged in session back to the login screen.

I just updated to Public Beta 2 and I have the same problem - if I connect a display to the DisplayLink dock something crashes and I get sent back to the login screen. Everything else in the dock works though - ethernet, USB, etc.

If you are logged out when connecting the DisplayLink screen(s) then you've likely hit a macOS bug that is triggered by mirroring screens. It's probably the same issue it's currently happening with the eGPU kit.

On some systems mirror may be already set for the external screens so every time they are plugged in you'll automatically hit this issue.
A possible workaround is to delete all persistence information, so at the next plug in a default extended state can be chosen by macOS.

This is how to delete persistence information from Terminal. Please note that the following commands if entered incorrectly may delete any file on your system:

To clean user preferences:

rm -f ~/Library/Preferences/ByHost/com.apple.windowserver.*.plist

To clean global persistence:

sudo rm -f /Library/Preferences/com.apple.windowserver.plist

After a reboot the display settings will reset to default, which should be extending to the right and not mirroring.

Morning Carlo! I followed this instruction to see what happens. The following result occours:

Running on 17A306f
Run command, disconnect DisplayLink device, restart the computer.
Computer boots normally with just the laptop and Apple Monitor plugged in over Thunderbolt.
Plug in DisplayLink with HDMI monitor attached.
WindowServer crashes, brings me back to login screen. Login screen is sky blue with a mild gradient, the background is not the standard background.
When trying to log in the WindowServer crashes and sends back to login. Repeat until you disconnect the HDMI and login screen returns to normal and login process is successful.

I have installed the Alpha driver and so far so good.
The second screen gives me the right picture and the mouse is moving.
Monday at the office i will test the DisplayLink with 2 monitors.
Keep you posted.

I've installed the 4.0 Alpha as well and have been running it a couple of hours now. So far everything seems to be working great - dragging application windows to the DisplayLink screen and moving them around is very smooth. Maybe not quite on par with my Thunderbolt 2 connected displays but very close

One thing I noticed was that the macOS menubar renders correctly now - no more faulty transparency and greyed out menu items are also readable now. I assume it has to do with the Metal optimizations.

With the DisplayLink plugged in USB w/1 monitor attached and a 2nd monitor attached HDMI via thunderbolt, the built in screen remains completely blank and requires holding down the power button and rebooting to get the built-in display working. This happens when in clamshell mode and the DisplayLink device, power, and thunderbolt are disconnected, then shortly after the built-in screen is opened. This only happens when DisplayLink is plugged in. If there is only a thunderbolt monitor and it is in clamshell mode, it wakes correctly.